Cardiopulmonary Apparatus And Methods For Preserving Organ Viability

ABSTRACT

Apparatus and methods for providing extracorporeal blood circulation and oxygenation control include multi-stage de-airing of blood to provide automated cardiopulmonary replacement to preserve the viability or one or more organs in a clinically dead organ donor or harvested donor organ for subsequent transplantation to an organ receiver patient.

CROSS-REFERENCE TO RELATED APPLICATIONS:

This application is related to U.S. application Ser. No. 11/284,515filed Nov. 22, 2005 entitled Apparatus For Making Extracorporeal BloodCirculation Available, which is incorporated herein by reference in itsentirety. This application is also related to European PatentApplication No. EP 04 027 855.8 filed on Nov. 24, 2004 entitledVorrichtung zur Bereitstellung eines estrakorporalen Blutkreislaufs(Device For Providing An Extracorporeal Blood Circuit), the disclosureof which is also incorporated herein by reference.

This application is also related to U.S. application Ser. No. 11/554,524filed Oct. 30, 2006 entitled Apparatus For Making Extracorporeal BloodCirculation Available, which is also incorporated herein by reference inits entirety.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to cardiopulmonary apparatus and methodsfor preserving the viability of organs in an expired organ donor forsubsequent transplantation by providing extracorporeal blood oxygenationand circulation. The apparatus and methods are useful in a variety ofsettings including hospitals, remote areas, accident sites, and duringtransport, for example in an ambulance, boat, or helicopter. Theapparatus and methods are useful to preserve the viability of organs ina clinically dead patient for subsequent transplantation undercircumstances that presently prohibitive to donor organ preservation.

2. Description of Related Art

Perfusion of a deceased organ donor with oxygenated blood must beinitiated quickly after the organ donor dies in order to preserve theviability of the organ(s) to be transplanted. Heart-lung andcardiopulmonary assist machines are known but their use in emergency,transport, and field situations is hindered, in part, by the relativelylong period of time and the requirement for well trained specialists forpriming the machines and safely bringing them into operation.

During machine priming, a liquid is used to fill the blood-conductingcomponents of the heart-lung machine. The priming liquid must be ventedor deaerated prior to connection with the organ donor's vascular systemand initiating heart-lung machine operation in order to eliminate airbubbles, which can cause thrombosis and damage organs. Known heart-lungmachines require considerable time as well as a trained perfusionspecialist for priming and operation.

The apparatus and methods of the present invention overcome theaforementioned limitations of prior art heart-lung machines by providingfor a compact and portable heart-lung machine that can be primed andready for operation in less than about 10 minutes. Priming of theextracorporeal blood circuit with priming liquid and de-airing isperformed with little or no human intervention. The present heart-lungmachine is self-contained and has an internal power supply, and may beconnected to an external power supply such as an on-board power supplyof an emergency land, air, or sea transport vehicle. Furthermore, noperfusion specialist is required for set up or operation and the machinemay be constructed to meet requirements for regulatory approval fortransport use. The machine may for instance in particular meetrequirements of the EN 1789 standard for use in humid environments,water subjection, and pass shake and crash tests involving up to 9-10 gforces.

The present invention is made possible, in part, by a number ofadvancements in heart-lung machine technology including a fast-closingclamp, a fast-priming extracorporeal blood oxygenation, deaeration andcirculation system, and an air bubble detection system, which aredescribed in co-assigned U.S. application Ser. No. 11/284,515 filed Nov.22, 2005; Ser. No. 11/366,342, now U.S. Pat. No. 7,597,546 filed Mar. 2,2006; Ser. No. 11/366,914, now U.S. Pat. No. 7,367,540 filed Mar. 2,2006; and Ser. No. 11/544,524 filed Oct. 30, 2006, which areincorporated by reference herein in their entirety. The apparatus andmethods of the invention are also made possible, in part, by amultistage air removal system and various other components andprocedures described herein.

BRIEF SUMMARY OF THE INVENTION

In one aspect, the invention is a method for maintaining the viabilityof organs for subsequent transplantation after the death of an organdonor by connecting the donor's circulatory system to a heart-lungmachine that is configured for rapid filling and priming by a primingfluid as well as rapid and safe transition to an operational mode. Theheart-lung machine comprises a base module and an patient module withpivot means at the base module and/or at the patient module to pivot thepatient module relative to the base module about a horizontal axis froma filling position into an operating position.

In a second aspect, the invention is a method for maintaining theviability of an organ for subsequent transplantation after the death ofan organ donor by connecting the donor's circulatory system to aheart-lung machine that automatically (i.e. without human intervention)detects air bubbles in blood conducting components of the machine,redirects the blood flow through the blood circulating components toprevent the bubbles from entering the donor's circulatory system,removes the bubbles from the circulatory system and, once air bubblesare no longer detected, resumes normal operation. This increases safetyof a portable device for the provision of an extracorporeal bloodcircuit such as is described in U.S. patent application Ser. Nos.11/284,515 and 10/839,126, which are incorporated by reference herein intheir entireties.

In a third aspect, the invention is a method for maintaining theviability of organs for subsequent transplantation after the death of anorgan donor by connecting the donor's circulatory system to a heart-lungmachine that comprises a fast acting clamp configured to close anarterial line when a bubble is detected in the blood circulatingcomponents of the heart-lung machine.

In a fourth aspect, the invention is a method for maintaining theviability of organs for subsequent transplantation after the death of anorgan donor by connecting the organ donor's circulatory system to aheart-lung machine that comprises a hose roller pump configured toremove air from a blood reservoir in the heart-lung machine.

Handling may be done by any trained hospital staff and there is no needor necessity of a clinical specialist, such as a perfusionist, or cardiotechnician, to be present for operation of the heart-lung machine. Theseactivities, including fast-priming, air bubble detection, air removalsystem, etc. are necessary for an automated function of the heart-lungmachine.

The heart-lung machine is further a mobile, self-contained heart-lungmachine and, in some embodiments, comprises a plurality of modules,including for example two or three modules.

Advantageous embodiments of the invention are described in thedescription, in the drawings and in the dependent claims. Further areasof applicability of the present invention will become apparent from thedetailed description provided hereinafter. It should be understood thatthe detailed description and specific examples, while indicating thepreferred embodiment of the invention, are intended for purposes ofillustration only and are not intended to limit the scope of theinvention.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a perspective view of a portable heart-lung machine;

FIG. 2 is a perspective view of the control module of the heart-lungmachine of FIG. 1 connected to a mount of the base module;

FIG. 3 is a perspective view of some blood-conducting components of thepatient module in the filling position;

FIG. 4 is the representation of FIG. 3 in the operating position, but ina view from the rear; and

FIG. 5 is a diagram showing the individual components of a heart-lungmachine according to the invention.

FIG. 6 shows a schematic representation of the individual components ofa heart-lung machine according to the invention.

FIG. 7 is a lateral section through a fast closing (quick action) clamp.

FIG. 8 is a lateral plan view of a fast closing clamp.

FIG. 9 is a plan view in the direction III indicated in FIG. 8.

FIG. 10 a is a detail of the sectional view of FIG. 7.

FIG. 10 b is a schematic of a cross-sectional view in an axial directionof view, designated by IVa in FIG. 10 a, of a blocking bar.

FIG. 11 is a schematic of a fast closing clamp not shown in FIGS. 7-9.

FIG. 12 is a side view of a peristaltic hose pump.

FIG. 13 is a mating piece of a hose pump.

FIG. 14 is a support element of a hose pump.

FIG. 15 is a support plate of the hose pump.

FIG. 16 is a perspective view of a side of a drive plate of a hose pump.

FIG. 17 is a perspective view of the drive plate of FIG. 16 on that sidewhich is remote from the support plate.

FIG. 18 is a section through the drive plate of FIGS. 16 and 17 alongthe line VII-VII.

FIG. 19 is an enlarged representation of a coupling device of a hosepump.

FIG. 20 is a diagram of an exemplary multi-stage air removal system.

FIG. 21 is a flow chart showing method steps exemplary of the presentmethods.

DETAILED DESCRIPTION OF THE INVENTION

In one embodiment, the apparatus and methods involve a heart-lungmachine configured for rapid filling and priming by a priming fluid aswell as rapid and safe transition to an operational mode. The heart-lungmachine comprises a base module and a patient module with pivot means atthe base module and/or at the patient module to pivot the patient modulerelative to the base module about a horizontal axis from a fillingposition into an operating position.

The patient module can be pivoted in a guided manner relative to thebase module by the pivot means, whereby the position and orientation ofindividual components of the extracorporeal blood circuit is modified sothat air bubbles, which cannot escape while the machine is in thefilling position, can be removed from the system at or after thetransition to the operating position via venting lines. The filling andventing of the patient module can take place in approximately 10minutes, whereas comparable apparatus in accordance with the prior artrequire approximately 20 minutes for this procedure.

An automated, even quicker priming may be provided by apparatus andmethods described in concurrently filed patent applications of the sameapplicant as the present application having obtained application numbersEP10194069.0, EP10194070.8, and EP10194071.6 (which correspond to U.S.Provisional Application Nos. ______, ______ and ______, filed on evendate herewith), which hereby are incorporated herein by reference intheir entirety for all purposes. Embodiments of these apparatus andmethods when incorporated in the present invention have a number ofadvantages, including fully automatic priming and air removal, while thebelow described (90°) pivoting process for priming is not necessary.

In one preferred embodiment, there is approximately 90° between thefilling position and the operating position, which has the advantagethat any air bubbles can reliably escape from the blood-conductingcomponents. A blood reservoir is provided in the patient module and isarranged at an inclination of approximately 45° to the horizontal bothin the filling position and in the operating position. This has theconsequence that the blood reservoir again has the same orientationrelative to the horizontal after a rotation of the patient module by 90°so that the same flow conditions result inside the reservoir before andafter the pivoting. A centrifugal pump head having a central inlet and atangential outlet can be arranged in the patient module such that theinlet is oriented vertically upwardly in the filling position andhorizontally in the operating position. In this manner, the pump headcan be filled with priming liquid from above without air bubblesremaining in the pump head during this process. It can likewise beadvantageous in this process to provide the centrifugal pump head with atangential outlet, which is arranged at the bottommost position of thecentrifugal pump head in the operating position. This ensures that airis not pumped into the patient's circulatory system by the centrifugalpump when the pump is in the operating (operational) position.

The heart-lung machine may comprise an arterial filter having a ventingoutlet arranged in the patient module such that the venting outlet isoriented horizontally in the filling position and vertically upwardly inthe operating position. Consequently, air inside the arterial filter,which is still present in the filter after the filling with primingliquid, can escape upwardly via the venting outlet after a pivoting intothe operating position.

The pivot means provided can be provided in the most varied designs,such as a mount for the patient module pivotally supported at the basemodule. In this case, the patient module only has to be coupled to themount in order to permit a guided pivot movement. It is particularlyadvantageous in this process for the pivot means to include a guideprovided at the mount and at the patient module. In this case, thepatient module can also be used to ensure the guided pivot movement. Itis also possible to connect the patient module to a further module, forexample to a control module, and to fasten the unit of the patientmodule and control module to the mount. In this case, the guide can beprovided at the mount and at the control module. It is also possible,for example, to provide a pivot bearing at the base module into whichthe other module or other modules are inserted.

The patient module is preferably in the operating position after beingplaced onto the base module since, in this case, a fast removal of thepatient module from the base module is ensured without a pivoting havingto be carried out beforehand. The base module may comprise a devicestand, which is provided with a pivotal hook to hang the apparatus onsuitable counter unit, such as the frame of a bed, or a transportationcontainer unit for organs. The control module and the patient module mayalso be integrated into a stand alone unit that is operated without thebase module. In some embodiments the hook is thus not present, which mayprovide for an alternative that is advantageous for some transportationsituations, such as during transportation of organs for subsequenttransplantation.

A method for putting the heart-lung machine into operation comprisesbringing the patient module into the filling position, in which fillingposition the blood-conducting components are filled with a primingliquid. The patient module is subsequently pivoted relative to the basemodule, preferably by about 90°, into the operating position. The pumphead provided in the patient module can be driven prior to the pivotingin order to pump the already filled-in priming liquid and thereby tofurther vent the blood-conducting components.

One embodiment of the heart-lung machine shown in FIGS. 1 to 4, iscomposed of three modules: a base module B comprising a device stand 10,a control module S and a patient module P comprising extracorporealblood-conducting components. The patient module P is coupled via latchelements (not shown) to the control unit S to form a unit and this unit,consisting of the control module S and the patient module P isreleasably latched to a mount 12 of the base module B.

As FIG. 1 shows, the device stand 10 may be made from tubular materialand has a pivotal hooking means 14 at its upper side which is bent toform a hook at its upper side to permit hanging of the unit, e.g. to aframe of a bed. The pivotal hook 14 can be pivoted downwardly by 180°from the position shown in FIG. 1 and can be plugged into two holdingclips 16, 17 so that the pivotal hook 14 is not in the way of themounting of the control module S and of the patient module P.

The device stand 10 is permanently connected to a carrier element 20 ofthe base module B which has a plug socket 22 for a mains cable. Themount 12 is pivotally supported in the carrier element 20. An operatingpart 24 is foldably fastened to the left hand side of the carrierelement 20 in FIG. 1 and has a touch screen 26 which represents an inputand output means for a control device (computer) provided in the basemodule. The carrier element 20 and the non-folded operating part 24 forman annular jacket for the unit of mount 12, control module S and patientmodule P. The operating part 24 must be unfolded open to the left fromthe position shown in FIG. 1 to mount or remove the unit of controlmodule S and patient module P.

FIG. 2 shows the mount 12 of the base module B of FIG. 1 to which thecontrol module S is releasably connected by means of latch connections28, 30. The patient module P is not shown in FIG. 2 for a simplifiedrepresentation. A unit of control module S and patient module P mustalways be plugged onto or removed from the mount 12 in operation. Thecontrol module S supplements the disk-segment shaped geometry of themount 12 and a handle 32 is located at the upper side of the controlmodule S with which the unit of control module S and patient module P,on the one hand, but also the whole heart-lung machine, on the otherhand, can be handled when the three modules are fastened to one anotheras shown in FIG. 1.

To pivot the patient module P relative to the base module B about ahorizontal axis from a filling/priming position into an operatingposition, the mount 12 of the base module B is equipped with two guiderails 34 which are parallel, provided at the outer periphery andcooperate with adjoining guide rails 36 of the control module S. Theguide rails 34 and 36 form a continuous guide structure with the aid ofwhich the unit of mount 12, control module S and patient module P can bepivoted relative to the base module B. The guide rails 34 of the pivotmount 12 are provided with a cut-out 38 with whose aid the pivot mount12 can be guided over two rollers (not shown) provided at the carrierelement 20 so that the pivot mount 12 can be pivoted on the supportelement 20 of the base module B. The toothed arrangement recognizable inFIG. 2 serves for the engagement of a damping mechanism ensuring auniform and damped pivot movement.

To assemble the pivot mount 12 with the support element 20, the pivotmount 12 is first brought into a substantially vertical position and thecut-outs 38 are guided via the rollers (not shown) provided at thecarrier element 20, whereupon the pivot mount 12 can subsequently bepivoted into the position shown in FIG. 1. After folding the operatingpart 24 open, the previously assembled unit of control module S andpatient module P can be latched on the pivot mount 12. To pivot thepatient module P from the present operating position into a fillingposition, the now formed unit of control module S, patient module P andpivot mount 12 can be pivoted by 90° by pivoting down the handle 32 sothat the control module S is in the position in which the pivot mount 12was previously located. In this filling position, the blood-conductingcomponents of the patient module P are in the orientation shown in FIG.3 with respect to the horizontal.

FIG. 3 shows some blood-conducting components of the patient module,with the patient module P having been rotated about 90°counterclockwise, starting from FIG. 1. The view shown in FIG. 3corresponds to a view from the other side of the patient module P incomparison with FIG. 1. The wall 40 of the patient module P standingperpendicular in FIG. 3 is thus disposed parallel next to the pivotmount 12, whereas the horizontally oriented wall 42 adjoins the controlmodule S. Furthermore, a plurality of hose connections are now shown inFIG. 3 for a better clear view. Reference numeral 44 designates acentrifugal pump head having a central suction inlet 46 and a radialoutlet 48 shown by broken lines in FIG. 4.

An approximately parallelepiped shaped blood reservoir 50 is installedat a position of 45° in the patient module P and its outlet 52 isconnected to the inlet 46 of the centrifugal pump head 44 via a hoseline (not shown). Venting lines 54 are located at the upper side of theblood reservoir 50. The inlet into the blood reservoir 50 coming from avenous connection is arranged approximately at the centre of the bloodreservoir and cannot be seen in FIGS. 3 and 4. It can be recognized inFIGS. 3 and 4 that an arterial filter 56 is provided in the patientmodule P which has a cylindrical shape, with a tangential inlet 58 and acentral axial outlet 60 being provided. A venting connection 62 isprovided centrally at the end face of the filter disposed opposite theoutlet 60.

Further components shown of the patient module P are an oxygenator 64and various connection elements which are provided at the wall 42disposed adjacent to the control module S and which serve for thecooperation with terminals, sensors or plug connections, since allblood-conducting components are provided in the patient module P,whereas control components such as the pump drive, valves and otherelectrical control elements are arranged in the control module S. FIG. 4shows the representation of FIG. 3 in the operating position, whichcorresponds to the representation of FIG. 1 in which the control moduleS and the wall 42 of the patient module P contacting it are orientedvertically.

As a comparison of FIGS. 3 and 4 shows, there is 90° between the fillingposition (FIG. 3) and the operating position (FIG. 4), with the bloodreservoir 50 provided in the patient module P being arranged in bothpositions at an inclination of 45° to the horizontal, since it isinstalled at 45° in the patient module. The centrifugal pump head 44 isarranged such that the central inlet 46 is oriented vertically upward inthe filling position (FIG. 3) and horizontally to the side in theoperating position (FIG. 4). The outlet 48 (not shown in FIG. 3) of thepump head 44 is arranged at the bottommost position of the centrifugalpump head 44 in the operating position shown in FIG. 4 so that theoutlet 48 lies beneath the inlet 46.

The arterial filter 56 is also arranged within the patient module suchthat the venting outlet 62 is oriented horizontally in the fillingposition and vertically upwardly in the operating position (FIG. 4). Theinlet 58 is oriented vertically downwardly in the filling position andhorizontally in the operating position, whereas the outlet 60 isoriented horizontally in the filling position and vertically downwardlyin the operating position.

FIG. 5 shows the different components of the heart-lung machine inaccordance with the invention in which the blood coming from a venousconnection V is guided via a line 70 into the blood reservoir 50 andflows from there via the outlet 52 into the inlet 46 of the centrifugalpump 44. It is pumped from there via the outlet 48 into the oxygenator64 and flows from there via the arterial filter 56 to the arterialconnection A and from there back into the body of the organ donor. Aninternal bypass, which can be switched via a valve 72, is designated byreference numeral 71. Reference numeral 73 designates a valve for theinflow line PR with which priming liquid can be guided into the circuit.Reference numerals 74, 75, and 76 each designate pressure sensors.Venting valves are designated by reference numerals 77, 78, and 79, withthe valves 77 and 78 switching the vent paths into the upper region ofthe blood reservoir 50 not filled with blood and the venting valve 79controlling the venting from the blood reservoir. Reference numeral 80designates a bubble sensor, which controls an arterial quick actionclamp 82 provided in the arterial outlet A if air bubbles are detected.Reference numeral 84 designates a flow sensor and reference numeral 86an electrical interface. The oxygenator 64 is provided with inflow linesand outflow lines for water and oxygen to effect an enriching of theblood with oxygen and a temperature control of the blood. In some casesthe blood temperature may be controlled to maintain a normal bodytemperature of 37 ° C., or a reduced temperature to aid the preservationof organ viability for subsequent transplantation.

To put the heart-lung machine described above into operation, startingfrom the representation of FIG. 1, the pivotal hook 14, if present, isfirst pivoted downwardly by 180° and the operating part 24 is folded tothe left. Subsequently, the total unit consisting of the control moduleS, the patient module P and the pivot mount 12 can be pivotedcounterclockwise so that the filling position is reached.

Priming liquid, which first (cf. FIG. 5) fills the blood reservoir andfrom there the centrifugal pump head 44, is supplied via the connectionPR in the filling position. The air located in the hosing is largelyremoved from the system in this process by the priming liquid arrangedabove the machine on filling, with air bubbles, however, remaining inthe upper region of the arterial filter 56 and in horizontal lineportions.

When the blood reservoir 50 is almost filled, the centrifugal pump head44 is set into rotation comparatively slowly, whereby the priming liquidis pumped through the system and further air residues are removed fromthe system. After a time period of approximately 20 seconds, furthercomponents—such as the oxygenator 64—are also filled with priming liquidso that the pump can be stopped and the unit of the control module S,patient module P and pivot mount 12 can be pivoted back into theoperating position. After these pivoting back by 90°, that air can alsoescape which had remained in the arterial filter 56 and in horizontalline portions. A complete filling and venting of the patient module canthus be achieved within a time period in the order of magnitude ofapproximately 6 to 10 minutes.

In one embodiment, the heart-lung machine is a mobile, self-containedheart-lung machine comprising a battery power supply configured to powerthe heart-lung machine and particularly well suited for use in the fieldand for emergency use. In another embodiment, the heart-lung machine isa mobile, self-contained heart-lung machine comprising a battery powersupply and/or connectors for an external electrical power supply from atransport vehicle with the heart-lung machine configured to operate onbattery power and/or the external electrical power supply of thetransport vehicle.

In a second embodiment, the apparatus and method of the inventioninvolve a heart-lung machine comprising a blood reservoir, a blood pump,and a bubble detector for the detection of air bubbles between venousand arterial connections to the patient circulatory system. Bloodentering at the venous connection is pumped by the blood pump throughthe blood reservoir and, optionally, through further blood-conductingcomponents via the bubble detector to the arterial connection. Anarterial line located downstream of the bubble detector leads to thearterial connection and can be closed by an arterial quick action clamp.If the bubble detector detects an air bubble, the arterial quick actionclamp can be closed immediately so that the air bubble cannot enter intothe organ donor's blood circulation from the arterial line.Simultaneously, the blood pump is stopped, a bypass clamp is opened, andthe blood pump is restarted, so that the blood is guided back into theblood reservoir through a bypass. The blood reservoir is connected to afurther pump, which removes air from the top of the blood reservoirwhere air bubbles collect. As soon as the bubble detector no longerdetects any air bubbles, the arterial quick action clamp is opened againand the bypass clamp is closed.

In accordance with an advantageous embodiment of the invention, a bloodoxygenator is arranged between the blood pump and the bubble detector.The oxygenator comprises a membrane that is impermeable to air bubbles,which contributes to the elimination of air in the system. An arterialfilter configured to collect and holds back microparticles which haveentered into the blood as well as gas bubbles can furthermore beprovided in front (upstream) of the bubble detector.

It is particularly advantageous for multiple blood-conducting componentsof the apparatus such as an oxygenator or an arterial filter to beconnected to the blood reservoir via a venting line that primarilyserves for flushing and venting during a priming process before theapparatus is placed into operation to pump blood. The venting linecomprises of clamps that can be used to open and close each venting lineduring priming. The venting clamps can, however, also be opened brieflyduring the operation of the apparatus at regular time intervals so thatair which has collected in the blood-conducting components is conveyedinto the blood reservoir. The air then rises to the surface in thereservoir and can be extracted by a pump provided for this purpose. Theventing line is connected to blood-conducting components in each case atthe side of the components disposed upwardly during operation so thatupwardly rising air bubbles migrate into the venting line. The regularventing of the blood-conducting components prevents the saturation ofblood with air and reduces the risk of an air bubble moving up to thebubble detector.

The pump extracting the air from the blood reservoir is preferably aroller pump, which can additionally have a clamping function. Such apump is described in U.S. patent application Ser. No. 11/366,342 andpermits the extraction of air from the blood reservoir with simplemeans, with it being ensured by the clamping function that no air canflow in the opposite direction, i.e. into the reservoir, even when thepump is switched off.

In accordance with an advantageous embodiment of the invention, the airextracted from the blood reservoir is pumped into an air containerarranged downstream of the pump extracting air from the blood reservoir.The total extracorporeal blood circuit thereby remains closed toward theoutside. A simple plastic pouch can serve as the air container.

Additional protection from air bubbles in the blood exiting theapparatus can be achieved by configuring the blood reservoir to comprisean inlet region separated from an outlet region by a screen unit whichis a membrane permeable for blood, but impermeable for air bubbles.

In accordance with a further advantageous embodiment of the invention,means are provided for the monitoring of the filling level of the bloodreservoir. A first sensor is preferably provided which detects whetherthe filling level reaches a first threshold value. A second sensordetects whether the filling level falls below a second threshold valuelying below the first threshold value. The corresponding information canbe passed on to an electronic control unit of the apparatus so that theroller pump can be switched on to extract air from the blood reservoirwhen the filling level falls below the first threshold value. The airwhich collects in the blood reservoir in bypass operation afterdetection of an air bubble or on a regular venting of blood-conductingcomponents is thus extracted automatically as soon as a predeterminedamount of air is present in the reservoir. As further security, theblood pump can be switched off if the filling level falls below thesecond threshold value. In this case, an alarm signal is simultaneouslyoutput. It is possible for the filling level of the reservoir to fallbelow the second threshold value, for example, if the venous connectionis not properly connected to the patient's blood circulation, but hasbecome loose so that air is pulled into the blood conducting components.In such cases, the described filling level monitoring switches the bloodpump off immediately.

In accordance with a further advantageous embodiment of the invention,the bypass clamp is opened at regular time intervals for a short periodto flush any pooled blood from the upstream side of the bypass clamp.This prevents coagulation of any pooled blood, which might then enterinto the extracorporeal blood circuit after the bypass clamp is openedand, in the worst case, subsequently enter into the organ donor bloodcirculation via the arterial connection.

As a consequence of the described automated safety features present inthe heart-lung machine, an intervention by trained medical staff due toan error report is only necessary in an extreme emergency. In the normalcase, the apparatus in accordance with the invention can successfullyprevent air bubbles from entering into the blood circulation of theorgan donor connected to the apparatus without any human intervention.This prevents damage to any of the organs intended for transplantation,such as the heart, kidney, liver, and lungs.

A heart-lung machine according to the present invention may be used topreserve the viability of organs in an organ donor for subsequenttransplant. In this case the organ donor has died and has no brainfunction. Various terms are used to describe the state of the organdonor, including brain dead, clinically dead, or deceased.

FIG. 6 shows a schematic of a heart-lung apparatus according to theinvention. Patient blood entering through a venous connection V isguided via a line 70 into a blood reservoir 50 and moves from therethrough an outlet 52 and into an inlet 46 of a centrifugal pump 44. Theinlet 46 is arranged centrally at the pump head of pump 44 and blood ispumped through a tangential outlet 48 arranged at the bottom most pointof the pump head of the centrifugal pump 44 and into an oxygenator 64 towhich an oxygen supply line is connected. Blood enriched with oxygen issubsequently filtered in an arterial filter 56 and finally flows, in thenormal case, through an arterial line 168 and via an arterial connectionA back into the donor.

The blood reservoir 50 is split into an inlet region 50 _(in) and aseparate outlet region 50 _(out) by a membrane 128 that is permeable forblood, but prevents air bubbles entering into the outlet region from theinlet region. A bubble detector 80 is arranged between the arterialfilter 56 and the arterial connection A. As long as it does not detectany air bubbles, an arterial quick action clamp 82 in the arterial line168 remains open, while a bypass clamp 72 remains closed. Blood flow canbe continuously monitored by flow sensor 84, which measures blood flowin the arterial line 168.

If an air bubble is detected in the bubble detector 80, the arterialclamp 82 is closed immediately. The reaction path between the bubbledetector 80 and the arterial clamp is configured to be long enough thata detected air bubble cannot reach the clamp before the clamp is closed.The clamp 82 is preferably a fast-closing clamp, which closes in lessthan 300 ms, as described in co-assigned U.S. patent application Ser.No. 11/366,914. Clamp 82 is also called quick action clamp herein. Thesufficiently long reaction path and the speed with which the clampcloses advantageously prevents any air bubble detected by the bubbledetector 80 from reaching the arterial connection A. Simultaneously, theblood pump 44 is stopped, the bypass valve or clamp 72 is opened, andthe blood pump 44 is re-started, so that the blood, together with thedetected air bubble, flows via a bypass 71 back into line 70 and intothe blood reservoir 50.

In the blood reservoir 50, air bubbles rise upwardly so that blood islocated at the bottom in the reservoir 50 _(out), and air collects atthe top 50 _(in). Means 122 for the monitoring of the filling level ofthe blood reservoir are electronically coupled, for example via anelectronic control unit, to a hose roller pump 170 configured for theextraction of air from the reservoir. The hose roller pump 170 may be,for example, a hose pump as disclosed in U.S. application Ser. No.11/366,342. As soon as the monitoring means 122 of the filling level ofthe blood reservoir 50 reports that the filling level has fallen below afirst threshold value, the hose roller pump 170 is switched on to removeair from the top of the reservoir 50 _(in) and pump the air into a wastecontainer 180. The hose roller pump 170 has a clamping function so thatit acts as a clamp if it is not actively pumping to prevent a backflowof air into the blood reservoir 50. If the filling level of the bloodreservoir falls further, despite the removal of air by the hose rollerpump 170, below a second threshold value, the centrifugal pump 44 isswitched off and an alarm, for example an audible and/or visible signalis output.

The oxygenator 64 and the arterial filter 56 are each connected to theupper region of the blood reservoir 50 _(in) by a venting line 96provided with venting valves 92, 94. The venting line first serves forthe flushing and venting of the heart-lung machine during a primingprocedure before it is put into operation. In this procedure, a primingliquid is filled in via a priming connection PR and priming circuit(dashed line passing through valve 90) and the extracorporeal bloodcircuit is vented. The venting clamps 92 and 94 are normally closedduring the operation of the heart-lung machine but are, however, openedbriefly at regular time intervals, for example every 10 to 15 minutes,so that accumulated air in the oxygenator or the arterial filter isguided into the reservoir 50 for removal from the system.

Pressure sensors 74, 75 monitor the pressure before (upstream of) andafter downstream of) the oxygenator. The measured values of the pressuresensors are forwarded to a pressure monitoring unit 127 via a connection(not shown for reasons of clarity). An abnormal increase in the pressuredrop at the oxygenator 64 can be an indicator of clogging by coagulatedblood, and a need for action may be indicated, for example, bytriggering an audible and/or a visual signal. Additionally, theextraction pressure at which blood is extracted from the patient intothe line 70 is monitored using pressure sensor 76, which measures thepressure in the line connecting the blood reservoir 50 and the hoseroller pump 170. The measured result is likewise passed on to thepressure monitoring unit 127.

To avoid coagulation of standing or pooled blood in the bypass 71 inFIG. 6 beneath the bypass clamp 72 while the arterial clamp 82 is openand the bypass clamp 72 is closed, the bypass clamp 72 may be opened atregular time intervals for a short time to periodically flush the bypass71.

Arterial quick action clamp 82 shown in FIG. 6 is preferably a fastclosing clamp as shown in FIGS. 7-11. The view of FIG. 7 corresponds tothe cross-section indicated by A in FIG. 9.The hose 201 contacts a wall203, which is formed for example by the rear wall of a housing partreceiving the hose. A clamp jaw 205 is configured to be brought into aclamping position in the arrow direction by the fast closing clamp,pinching the hose 201 closed.

A holding apparatus 207 comprises an inner hollow space in which theclamp jaw 205 is guided. In the embodiment shown, the clamp jaw 205 isan internal piston and the holding apparatus 207 is an external piston,with the internal piston 205 being displaceably received in the externalpiston 207 and the external piston 207 being displaceably received in ahousing 209. A spring 217 is supported against a seat 216 inside theexternal piston 207 and a seat 218 is supported at the externalperiphery of the internal piston 205, said spring being undercompressive tension in the open position of the internal piston shown inFIG. 7.

The spindle 219 of a spindle drive comprises an external thread 221 inthe region in which it engages into the external piston 207, which has acorresponding mating thread at the internal periphery where the spindle219 passes through it. The spindle 219 is rotatably held in the housing209 in a bearing 223. The spindle is connected to a toothed wheel 225via the grub screw 227. The toothed wheel 225 meshes with a toothedwheel 229 which, in turn, meshes with a toothed wheel 231 that isconnected via a grub screw 233 to the axis of an electric motor 235which is fixedly installed in a holding plate 237.

The toothed wheel 229 is rotatably supported in the holding plate 237.The housing 209 is permanently connected to the holding plate 237. Ahollow space 215 is located in the external piston 207 and balls 213 canpartly enter into it, which project radially out of the internal piston205 in the latched state.

FIG. 8 shows the fast closing clamp of FIG. 7 in a lateral plan view.The direction of view visible in the plan view of FIG. 9 is indicated byIII in FIG. 9. The internal piston 205 comprises a radially outwardlyextending abutment bar 239, which is guided in an elongate hole 238 ofthe housing 209 (FIG. 8).

FIG. 10 a shows a detail of FIG. 7 in the region of the latch devicebetween the external piston 207 and the internal piston 205. The latchedstate is also shown in FIG. 10 a. The tip of the blocking bar 211 liesin the axial cut-out 206 of the rear part of the internal piston 205. Inthis process, the tip presses balls 213 outwardly through radialopenings 214 in the internal piston 205, which partly enclose the balls213. The tip of the blocking bar 211 is made in ball shape and taperedtoward the front so that it can easily be pushed between the balls 213.In the embodiment shown, three of the radial openings 214 are providedwith corresponding balls 213 at an angle of 120° to one another. The twoother openings are therefore not visible in the sectional representationof FIG. 10 a.

The balls 213 engage into a cut-out 215 in the external piston 207. Inthe state shown, the internal piston 205 cannot move out of the externalpiston 207 to the right since the balls 213 are fixed in the cut-out 215of the external piston 207. If the blocking bar 211 is pulled out of theaxial cut-out 206 of the internal piston 205 to the left, the balls canmove into the axial cut-out 206 and the internal piston 205 can be movedout of the external piston 207 to the right by the force of the spring217. The inward movement of the balls 213 is in particular facilitatedby the chamfering 220 of the cut-out 215. The right hand end of thespindle 219 can be recognized in FIG. 10 a with the thread 221, whichmeshes in an internal thread of the external piston 207.

Whereas FIG. 10 a shows a section through the fast closing clamp inwhich a ball 213 is sectioned precisely at the center. FIG. 7 shows asection in which no ball 213 is precisely cut. In this respect, thesectional planes of FIG. 7 and of FIG. 10 a are tilted with respect toone another by 30° around an axis which is, for example, defined by theblocking bar 211. This relationship is illustrated in FIG. 10 b, whichshows a view in the direction of the arrows IVa, which are given in FIG.10 a. A view in an axial direction of the tip of the blocking bar 211and of the balls 213 is shown in a schematic representation in FIG. 10b. S1 shows the sectional plane of FIG. 7, while S4 shows the sectionalplane of FIG. 10 a. The direction of view of the sectional plane, whichis the subject matter of FIG. 7, is designated by the arrows I in FIG.10 b. The direction of view of the sectional plane, which is the subjectmatter of FIG. 10 a, is designated by the arrows IV in FIG. 10 b. Theangle 13 indicated amounts to 60°, whereas the tilt angle of thesectional plans a amounts to 30°.

FIG. 11 shows a part of the quick action, fast closing clamp not shownin FIGS. 7-10 a, which is a mechanism that moves the blocking bar 211 inthe axial direction. The blocking bar 211 is connected via a hinge point212 to a rocker 241, which is rotatably supported at the point 243. Thisrocker is connected via a hinge point 249 to a metallic actuation bar247, which projects into an electromagnet 245. In this arrangement, thebar 247 moves to the right on a flow of current through theelectromagnet 245. The rocker rotates around the center of rotation 243and moves the blocking bar 211 to the left in the representation of FIG.11. A compression spring 248 biases the rocker 241, the actuation bar247, and the blocking bar 211 in the direction of their positions ofrest when the electromagnet 245 again has no current. The force of theelectromagnet 245 acts against the spring force of this spring 248.

When a bubble is detected in the hose 201, a signal is transmitted toput the electromagnet 245 under current for approximately 50 ms so thatthe actuation bar 247 moves into the electromagnet. The rocker 241rotates around the center of rotation 243 and pulls the blocking bar 211to the left. The blocking rod 211 thereby moves out of the axial hollowspace 206 (FIG. 10 a) of the internal piston 205. The internal piston205 is urged in the direction of the arrow (FIG. 7) by the spring forceof the spring 217. Since the blocking bar 211 no longer blocks the axialhollow space, the balls 213—facilitated by the chamfer 220—escape backinto this hollow space 206 and the latch connection between the internalpiston 205 and the external piston 207 is cancelled. The spring force ofthe spring 217 drives the internal piston 205 against the hose 201 andpinches it off against the rear wall 203 of the passage conducting thehose. It is, for example, sufficient to operate the electromagnet onlyfor approximately 50 milliseconds to trigger this action. The hose ispinched off after only around 100 milliseconds. The abutment bar 239guided in the longitudinal hole 238 in the housing 209 prevents theinternal piston 205 from being able to completely exit the housing 209on an unintentional triggering.

To move the internal piston back into its open position, the electricmotor 235 is switched on. The spindle 219 is driven via the toothedwheels 231, 229, and 225. The external piston 207 moves axially to theright out of the housing 209 by the spindle rotation. The internalpiston 205 is in the meantime still supported against the hose 201 orthe rear wall 203 of the passage. As soon as the external piston 207 andthe internal piston 205 are again completely pushed onto one another,the radial openings 214 in the internal piston 205 are again in theregion of the cut-out 215 inside the external piston 207. The tip of theblocking bar 211 can again push between the balls 213 which are in turnmoved radially outwardly through the openings 214 in the internal piston205. The blocking bar 211 is pushed into the axial cut-out 206 of theinternal piston 205 by the action of the spring 248 which acts on therocker 241 for this purpose. The balls 213 again engage into the cut-out215 in the external piston 207 as is shown in FIG. 10 a and latch theexternal piston 207 and the internal piston 205.

If the electric motor 235 is operated in the reverse direction, thespindle 219 pulls the external piston 207 to the left in therepresentation of the Figures. The internal piston 205 is also movedback due to the latching of the internal piston 205 in the externalpiston 207 and the fast closing clamp again moves to its open position.The spring 217 again starts to tense while the external piston 207 isagain pushed over the internal piston 205 and stores energy for a newtriggering process. It is possible in this way to trigger a furtherpinching process as required on the returning of the internal piston 205together with the external piston if e.g. a bubble is again detected inthe extracorporeal circuit during the return of the internal piston 205.

The hose roller pump 170 in FIG. 6 is preferably a peristaltic hose pumpas shown in FIGS. 12-19. The pump, as shown in FIG. 12, comprises asupport plate 310, which can be installed in a fixed position, and abore through which a drive shaft 312 is rotatably inserted. The rightend of the drive shaft 312 in FIG. 12 can be driven by a drive (notshown), for example by an electric motor, whereby a rotor 314 attachedto the left end of the drive shaft 312 in FIG. 12 likewise rotates. Therotor 314 has a plurality of rollers 316 which are distributed over itsperiphery and which serve in a known manner to press fluid (e.g. air orblood) through a flexible hose (not shown).

A mating piece 318, shown in a perspective view in FIG. 13, is screwedbeneath the rotor 314 to the left side of the support plate 310 in FIG.12 and has two vertical blind bores 320 and 321, on the one hand, andtwo V-shaped grooves 322 and 323, on the other hand, which extend at anangle to the horizontal and extend inside one and the same verticalplane. The mating piece 318 furthermore has an approximatelysemi-circular opening in which the rotor can rotate freely.

FIG. 12 shows that a support element 326 above the rotor 314, which ismovable in the direction of the double arrow by a predetermined distancein the direction toward the rotor 314 or by a predetermined distanceaway from the rotor 314. FIG. 12 shows the pump with the support elementcompletely moved away from the rotor 314 by the predetermined distance.

Two guide pins 328 (only one is shown in FIG. 12), which are insertedinto the blind bores 320 and 321 of the mating piece, guide the supportelement 326. As FIG. 14 shows, the support element 326 likewise has twoblind bores 330 (only one is shown) so that the support element 326 isguided by the guide pins 328. FIG. 14 shows that the support element 326also has two V-shaped grooves 332 and 334 which, together with thegrooves 322 and 323 of the mating piece 318, form a clamping device inwhich the hose can be clamped by a movement of the support element inthe direction toward the rotor. A groove 336 provided at the rear sideof the support element 326 serves for the insertion of a metal piece topermit a contact free position detection with the help of a sensor (notshown). A blind bore 338 is provided centrally at the rear side of thesupport element 326. A pin 340 is inserted into this blind bore, asshown in FIG. 12, extending through an elongate hole 341 in the supportplate 310 and simultaneously serving as an end abutment for the movementof the support element 326. The pin 340 projects somewhat from thesupport plate 310 on the side thereof opposite to the support element326 and the projecting end of the pin 340 is inserted into a plainbearing 342 which is movable in a spiral groove 344 (FIG. 17) of a driveplate 346.

The drive plate 346 is shown in more detail in FIGS. 16-18 and is placedfreely rotatable onto the drive shaft 312 via a plain bearing 348. FIG.17 shows a view of that side of the drive plate 346 which faces thesupport plate 310. The spiral groove 344 extends from the outer rim ofthe drive plate 346 in the direction of the center, with the spiralgroove extending over an angle of somewhat more than 180°. A ring groove350 is provided at the interior of the spiral groove 344 and receives afixed position cam guide 352, which is made integrally with the supportplate 310 (FIG. 15). FIGS. 15 and 19 show that the fixed position guidecam 352 has a rising and a falling flank of the same gradient. In thisprocess, the guide cam 352 is curved in the peripheral direction suchthat it fits into the ring groove 350 of the drive plate 346.

FIG. 16 shows the side of the drive plate 346 disposed at the bottom inFIG. 17. A curved recess is provided at this side of the drive plate346, which has two guide chamfers 354 and 356 whose lowest point formsan opening 358 through which a passage into the ring groove 350 iscreated. This passage serves for the passing through of a drive pin 360,which serves as a coupling member between the drive shaft 312 and thedrive plate 346.

FIG. 12 shows that a drive plate 362 is rotationally fixedly connectedto the drive shaft 312, with the drive pin 360 being resilientlysupported in a sleeve 364 provided at the drive plate 362 such that itis displaceably supported against the force of the spring in the axialdirection of the drive shaft 312. When the drive shaft 312 thus rotates,the drive plate 362 and also the drive pin 360 rotate together with it.In this process, the drive pin 360 presses against the drive plate 346due to the spring and the front end of the drive pin 360 runs on thedrive plate on an orbit which is indicated by a broken line in FIG. 16.If, in this process, the drive pin 360 moves into the region of theguide chamfers 354 and 356, the front end of the drive pin 360 moves onthese guide chamfers until it moves through the opening 358 in the driveplate.

The starting position is the situation shown in FIG. 12 in which thesupport element 326 has been moved away from the rotor 314 by thepredetermined distance. In this position, the drive pin 360 is locatedin the situation shown in FIG. 19 in which it projects through theopening 358 in the drive plate 346 and its front end lies on the fixedposition cam guide 352. If, in this process, the drive shaft 312 andthus the drive wheel 362 are moved against the arrow direction S, thedrive pin 360 is moved to the right in FIG. 19 and first runs on thefixed position cam guide 352 and subsequently on the guide chamfer 356of the drive plate 346 which merges constantly into the left hand flankof the fixed position cam guide 352. Subsequently, the drive pin 360runs on the orbit shown by a broken line in FIG. 16 until it again movestoward the guide chamber 354 and slides along on this until thesituation of FIG. 19 again results. This means that the drive shaft canbe rotated as desired against the arrow direction shown in FIG. 19,without the drive plate 346 moving.

After a flexible hose has been inserted into the intermediate spacebetween the support element 326 and the rotor 314, the direction ofrotation of the drive shaft 312 is reversed and now runs in thedirection of the arrow S shown in FIG. 19. However, this means that thedrive pin 360 abuts the lower end of the guide chamfer 354, so that, ona further rotational movement, the drive plate 346 is taken along by thedrive pin 360 and likewise rotates in the direction of the arrow S. Inthis process, the front end of the follow pin runs along the fallingflank of the cam guide 352 until it revolves on the orbit shown by abroken line in FIG. 15.

On this rotation of the drive plate 346, the plain bearing 342simultaneously runs in the spiral orbit 344 and thereby moves in thedirection of the axis of rotation, whereby the pin 340 in the elongatebore 341 is likewise moved in the direction of the axis of rotation.Consequently, the support element 326 is moved by the predetermineddistance in the direction toward the rotor 314 such that the flexiblehose (not shown) is respectively clamped between the V grooves 322 and332, and 323 and 334. At the same time, the hose is clamped between thesupport element 326 and the rotating rollers 316 of the rotor 314 sothat a pump effect is achieved.

After a complete revolution of the drive pin 360 on the orbit shown in abroken line in FIG. 15, said drive pin moves from the right side in FIG.19 back up to the cam guide 352 and subsequently slides upwardly on thisuntil the front end moves onto the guide chamfer 354 of the drive plate346 constantly adjoining the cam guide 352 at this point in time. Thedrive pin 360 then slides further upwardly on this guide chamfer 354until the front end of the drive pin 360 revolves on the orbit shown ina broken line in FIG. 16. When the drive shaft is rotated further in thedirection of the arrow S, the drive pin 360 can revolve for any desiredlength of time without effecting a movement of the drive plate 346. Onlywhen the direction of rotation is reversed again does the drive pin 360again couple with the drive plate 346 in that it moves through theopening 358 and slides downwardly on the fixed position cam guide 352.The front end of the drive pin 360 subsequently again revolves once onthe orbit shown by a broken line in FIG. 15 until the situation shown inFIG. 19 is the result.

One important advantage of the present apparatus and methods overexisting apparatus and methods is the ability to quickly provideextracorporeal blood circulation and oxygenation without the need for aspecially trained operator. Quickly and automatically priming theapparatus and then placing the apparatus into an automated operationalmode required is enabled by the safety features described herein.Various combinations and configurations of Quick-action (fast closing)clamps, vent lines, filters, air removal pumps, and other componentsachieve a level of safety that permits the automation of the heart-lungmachine and methods involving an automated heart-lung machine.

FIG. 20 shows a preferred embodiment of a multi-stage air removal systemproviding a level of safety that permits automated extracorporeal bloodcirculation and oxygenation. A screen filter with a suitable pore size,such as 120 μm, separates the blood reservoir 50 into two sections (FIG.5). Air bubbles having a diameter of greater than 120 μm cannot passthrough the screen from the venous blood input section of the reservoirto the output section of the reservoir.

An upper level fill sensor 122 a capable of distinguishing between gas(air) and liquid (blood) is connected to a roller pump 170 configured toremove air from the inlet portion of the blood reservoir. When the upperlevel sensor 122 a detects a liquid, the roller pump 170 is inactive.When the level of blood falls below the level of the upper fill sensor122 a, the sensor detects air and sends a signal to the roller pump 170,causing the pump to remove air from the top of the reservoir. Removingair from the reservoir results in a relative negative pressure withinthe reservoir that increases the rate at which blood is drawn into theinlet of the reservoir from the venous blood source.

A lower level fill sensor 122 b capable of distinguishing air from bloodis connected to a centrifugal pump 44 configured to pump blood from thereservoir 50 to an oxygenator 64. As long as the lower level fill sensor122 b detects blood, blood is pumped from the reservoir 50 to theoxygenator 64. When the lower level fill sensor 122 b detects air, itsends a signal to the centrifugal pump 44, causing the pump toimmediately stop pumping blood from the reservoir. This prevents thecentrifugal pump from emptying the reservoir and pumping air into thedownstream blood conducting components of the heart-lung machine.

The centrifugal pump 44 has a central inlet and a tangential outlet atthe lowest point of the pump head with respect to gravity. Should airenter the inlet of the pump, the rotation of the pump causes liquid inthe pump to move toward the outer wall of the pump head leading to theoutlet while any air is moved toward the center of the pump head andprevented from reaching the outlet. Any air in the pump remains in thetop center portion of the pump head, which successfully prevents even asmall volume of air from reaching the downstream blood conductingcomponents of the heart-lung machine.

The oxygenator 64 has a separate ventilation system where air rises toand is removed from the highest point of the oxygenator 64. A vent line(purgeline) 96 a is connected to the top of the oxygenator andconfigured to carry the air away from the oxygenator. In a preferredembodiment, the oxygenator vent line 96 a carries air from theoxygenator 64 to the blood reservoir 50 as shown in FIG. 20.

Oxygenated blood moves from the oxygenator 64 to a vented arterialfilter 56. A vent line 96 b (purge line) is connected to the highestpoint in the arterial filter 56 and removes air that is trapped by thefilter. In a preferred embodiment, the arterial filter vent line 96 bcarries air from the filter 56 to the blood reservoir 50.

The air bubble sensor 80 (detector) is positioned downstream of thearterial filter 56 and communicates with a quick-action clamp 82positioned on the arterial line leading to the arterial connection A andto a bypass clamp 72 located on a bypass line (not shown). In normaloperation without air bubbles, the quick-action clamp 82 is open and thebypass clamp 72 is closed. In response to the detection of an air bubbleby the bubble sensor 80, the quick-action clamp 82 on the arterial linecloses immediately. Then the bypass clamp 72 on the bypass line opens todivert blood flow away from the arterial connection A and back to theblood reservoir 50 through the bypass line. As the bypass clamp is not aquick action clamp, but an ordinary hose clamp, it opens much slowerthan the quick action clamp 82 closes. Therefore, when the quick-actionclamp 82 is activated, the blood pump is simultaneously stopped, and thebypass clamp is “slowly” opened. After a short delay period, when thebypass clamp is open, the blood pump is re-started. This is made toensure that the running blood pump does not generate undesired highpressures in the blood conveying system against the closed quick actionclamp 82 and the closed bypass clamp 72. Thus leakage caused byoverpressure in the system is effectively avoided. Once no air bubblesare detected in the bypass flow by the air bubble sensor and apredeteremined time interval has elapsed, the first and secondquick-action clamps revert to their normal operating positions.

An exemplary method according to the present invention is outlined inFIG. 21. First the heart-lung machine is primed, or filled, with apriming fluid such as sterile saline. Once initiated, the priming cantake place in an automated manner without human intervention. Themachine is then switched from the filling (or priming) mode into anautomated operational mode. Once primed, the machine is fluidly coupledto the circulatory system of the donor through a vein to the venouscoupling of the machine and through an artery to the arterial couplingof the machine. The method may include the addition of drugs or otheradditives to the blood by way of the heart-lung machine. For example, ananticoagulant may be added to the blood to prevent clotting. The organsto be donated may be sustained until transplantation using theheart-lung machine or they may be sustained by the heart-lung machine,harvested, and transported separately before transplantation. Theheart-lung machine may prevent decomposition of the organ(s) untilshortly before transplantation of the organ to a organ receiver. Theviability of one or more organs is maintained in the organ donor forsubsequent transplantation. When the organ is ready to be implanted tothe organ receiver, the donor body or harvested organ is disconnectedfrom the heart-lung-machine.

In addition, or alternatively, one or more harvested organs may be keptalive by means of the heart-lung machine after harvesting. The organsmay then be perfused during transport by the heart lung-machine. Organsin particular suitable for such transport after harvesting comprise, butare not limited to, the heart, lungs, liver, or limbs. However, this isunder certain circumstances not feasible for some organs, such as eyes.Under such circumstances certain organs, such as eyes, are preferablysustained and kept from decomposing, by perfusing the entire body of adeceased, brain dead, or clinically dead organ donor.

In this manner, the method allows for one or more organs to betransported from one location to another location for transplantation.Transport is in particular facilitated by using the heart-lung machinein accordance with the afore described embodiments. The organs may bekept in a condition that allows to prevent a decomposition of the organthat would occur without interaction of the heart-lung-machine with theorgan. Blood or a blood substitute liquid may be used in the method forperfusing the organ(s).

The description of the invention is merely exemplary in nature and,thus, variations that do not depart from the gist of the invention areintended to be within the scope of the invention. Apparatus and methodscomprising combinations of two or more of the various aspects and/orembodiments described herein and other variations are not to be regardedas a departure from the spirit and scope of the invention.

1. A method for providing extracorporeal circulation to a subjectcomprising the steps: a) priming a heart-lung machine with a primingliquid in a priming mode; b) switching the heart lung machine from thepriming mode to an operational mode; c) connecting a venous blood inleton the heart lung machine to a vein in the subject and connecting anarterial blood outlet from the heart lung machine to an artery in thesubject to form a closed extracorporeal blood circulation in fluidcontact with the circulatory system in the subject; and d) operating theheart-lung machine in said operational mode to take venous blood fromthe subject, oxygenate the venous blood, and return oxygenated blood tothe subject; wherein: said heart-lung machine comprises a centrifugalpump head having a central inlet and a tangential outlet; and saidcentral inlet to the centrifugal pump head is oriented vertically upwardduring priming step a) and horizontally during operating step d).
 2. Themethod of claim 1, wherein the subject is a deceased, brain dead, orclinically dead organ donor and the method further comprises method stepe) maintaining the viability of at least one organ of the organ donorfor subsequent transplantation.
 3. The method of claim 2, wherein saidtangential outlet of said centrifugal pump head is located at a bottommost position of the centrifugal pump head in the operating position instep c).
 4. The method of claim 2, wherein switching said step c)comprises rotating said centrifugal pump head about a horizontal axis.5. The method of claim 4, wherein said centrifugal pump head is rotatedabout a horizontal axis by approximately 90°.
 6. The method of claim 1,further comprising driving a pump head of the centrifugal pump prior tosaid switching step c) to vent blood-conducting components in theheart-lung machine.
 7. The method of claim 2, comprising maintaining theviability of said at least one organ of the organ donor by means of theheart-lung machine after harvesting of at least one organ, transportingsaid at least one organ to a transplantation location while perfusingthe at least one organ during transport by means of the heartlung-machine.
 8. The method of claim 2, comprising maintaining theviability of said at least one organ of the organ donor by means of theheart-lung machine before harvesting of at least one organ and duringtransporting said organ donor to a transplantation location whileperfusing the body of said organ donor during transport by means of theheart lung-machine.
 9. The method of claim 7, comprising transplantingsaid at least one organ to an organ receiver.
 10. A method for providingextracorporeal circulation to a subject comprising the steps: a) priminga heart-lung machine with a priming liquid in a priming mode; b)switching the heart lung machine from the priming mode to an operationalmode; c) connecting a venous blood inlet on the heart lung machine to avein in the subject and connecting an arterial blood outlet from theheart lung machine to an artery in the subject to form a closedextracorporeal blood circulation in fluid contact with the subjectcirculatory system; d) operating the heart-lung machine in saidoperational mode to take venous blood from the subject, oxygenate thevenous blood, and return oxygenated blood to the subject; and whereinsaid heart-lung machine comprises: a venous connection configured forreceiving blood from a vein of the subject; a blood reservoir separatedinto a blood-containing space and an air-containing space by a membranethat is permeable to blood but not to air bubbles, said blood reservoirconfigured to receive blood from said venous connection; a centrifugalpump having a central inlet and a tangential outlet and configured todraw blood from said blood reservoir and pump the blood into anoxygenator; an arterial filter located downstream of said oxygenator; abubble detector located downstream of said arterial filter and connectedby an arterial line to an arterial connection configured to deliveroxygenated blood to an artery of the subject; an arterial clamp disposedon the arterial line between the bubble detector and the arterialconnection; a bypass line connecting to said arterial line between thebubble detector and the arterial clamp and configured to transport bloodfrom the arterial line to the blood reservoir; and a bypass clampdisposed on the bypass line wherein: said operating of said heart-lungmachine comprises the steps of: e) pumping blood received from thesubject through the venous connection through a blood reservoir and anarterial line to an arterial connection; f) monitoring for air bubblesin the arterial line using said bubble detector; g) when the bubbledetector detects an air bubble, closing the arterial clamp and openingthe bypass clamp so that the blood is guided from the bubble detectorback into the blood reservoir; h) extracting air from the air-containingspace in the blood reservoir using an air extraction pump; and i) whenthe blood detector no longer detects an air bubble, opening the arterialclamp and closing the bypass clamp so that the operating stateprevailing before the detection of an air bubble is re-established. 11.The method of claim 10, wherein the subject is a deceased, brain dead,or clinically dead organ donor and the method further comprises methodstep of maintaining the viability of at least one organ of the organdonor for subsequent transplantation.
 12. The method of claim 11,comprising maintaining the viability of said at least one organ of theorgan donor by means of the heart-lung machine after harvesting of atleast one organ, transporting said at least one organ to atransplantation location while perfusing the at least one organ duringtransport by means of the heart lung-machine.
 13. The method of claim11, comprising maintaining the viability of said at least one organ ofthe organ donor by means of the heart-lung machine before harvesting ofat least one organ and during transporting said organ donor to atransplantation location while perfusing the body of said organ donorduring transport by means of the heart lung-machine.
 14. The method ofclaim 12, comprising transplanting said at least one organ to an organreceiver.
 15. The method of claim 10, wherein: said blood reservoircomprises a fill level detector in communication with said airextraction pump said centrifugal pump; said level detector and said airextraction pump are configured to activate said air extraction pump whenthe blood level detected by the fill level detector in the bloodreservoir falls below a first predetermined level; and said leveldetector and said centrifugal pump are configured to shut down saidcentrifugal pump when the blood level detected by the fill leveldetector in the blood reservoir falls below a second predeterminedlevel.
 16. The method of claim 15, wherein said fill level detectorcomprises two fill level sensors located at different positions in theblood reservoir.
 17. A method for maintaining the viability of organs ina deceased, brain dead, or clinically dead organ donor for subsequenttransplantation comprising the steps of: a) priming a heart-lung machinewith a priming liquid in a priming mode; b) switching the heart lungmachine from the priming mode to an operational mode; c) connecting avenous blood inlet on the heart lung machine to a vein in the organdonor and connecting an arterial blood outlet from the heart lungmachine to an artery in the organ donor to form a closed extracorporealblood circulation in fluid contact with the organ donor circulatorysystem; d) operating the heart-lung machine in said operational mode totake venous blood from the organ donor, oxygenate the venous blood, andreturn oxygenated blood to the organ donor; and e) maintaining theviability of at least one organ of said organ donor for subsequenttransplantation wherein said heart-lung machine comprises a peristaltichose pump comprising: a rotor rotatable by a drive shaft; a supportelement extending along a part of the rotor periphery; a flexible hoseinsertable between the support element and the rotor; a drive platerotatable about the drive shaft said drive plate comprising a spiralguide that guides the movement of the support element; wherein: thesupport element is movable by a predetermined distance in a directiontoward the rotor by rotation of the drive shaft in a first direction ofrotation; a ring groove is provided in the drive plate into which afixed position cam guide engages; and the drive plate has at least oneguide chamfer, whose lowest point is an opening in the base of the ringgroove, in the region of the opening on the side opposite the ringgroove.
 18. The method of claim 17, comprising maintaining the viabilityof said at least one organ of the organ donor by means of the heart-lungmachine after harvesting of at least one organ, transporting said atleast one organ to a transplantation location while perfusing the atleast one organ during transport by means of the heart lung-machine. 19.The method of claim 17, comprising maintaining the viability of said atleast one organ of the organ donor by means of the heart-lung machinebefore harvesting of at least one organ and during transporting saidorgan donor to a transplantation location while perfusing the body ofsaid organ donor during transport by means of the heart lung-machine.20. A method for maintaining the viability of organs in a deceased,brain dead, or clinically dead organ donor for subsequenttransplantation comprising the steps of: a) priming a heart-lung machinewith a priming liquid in a priming mode; b) switching the heart lungmachine from the priming mode to an operational mode; c) connecting avenous blood inlet on the heart lung machine to a vein in the organdonor and connecting an arterial blood outlet from the heart lungmachine to an artery in the organ donor to form a closed extracorporealblood circulation in fluid contact with the organ donor circulatorysystem; d) operating the heart-lung machine in said operational mode totake venous blood from the organ donor, oxygenate the venous blood, andreturn oxygenated blood to the organ donor; and e) maintaining theviability of at least one organ of said organ donor for subsequenttransplantation wherein: said heart-lung machine comprises a fastclosing clamp configured to alternately close and open an arterial linein said heart-lung machine, said fast closing clamp comprising: a) aclamp jaw with a clamping position, in which it can pinch off a hose,and an open position; b) a holding apparatus; c) a spring device whichbiases the clamp jaw with respect to the holding apparatus such that theclamp jaw is brought into the clamping position on the relaxation of thespring device; d) a latch device with which the clamp jaw and theholding apparatus can be latched to one another against the spring forceof the spring device in a latched position; and e) a return mechanismfor the movement of the holding apparatus relative to the clamp jawuntil the holding apparatus and the clamp jaw are in their latchedposition relative to one another while the clamp jaw is in the clampingposition, and for the movement of the holding apparatus together withthe clamp jaw into the open position of the clamp jaw after the clampjaw and the holding apparatus with the latching device have been latchedto one another.
 21. The method of claim 20, wherein said fast closingclamp jaw is in an open position that allows a flow of fluid through ahose; the clamp jaw is latched to a holding apparatus by a latch device;the relative longitudinal position between the clamp jaw and the holdingapparatus when latched together is a latching position; the latch deviceis manipulated to unlatch the clamp jaw from the holding apparatus; theclamp jaw moves in the longitudinal direction after being unlatched fromthe holding apparatus to a clamping position by a separating forcetending to move the clamp jaw away from the holding apparatus; the clampjaw prevents the flow of fluid through the hose while in the clampingposition; the holding apparatus is moved relative to the clamp jaw inthe longitudinal direction until the holding apparatus and clamp jaw arein the latching position relative to each other while the clamp jaw isin the clamping position; the clamp jaw is latched to the holdingapparatus using the latch device while the clamp jaw is in the clampingposition; and the holding apparatus and clamp jaw are moved whilelatched together until the clamp jaw is in the open position.
 22. Amethod for maintaining the viability of organs in a deceased, braindead, or clinically dead organ donor for subsequent transplantationcomprising the steps of: a) priming a heart-lung machine with a primingliquid in a priming mode; b) switching the heart lung machine from thepriming mode to an operational mode; c) connecting a venous blood inleton the heart lung machine to a vein in the organ donor and connecting anarterial blood outlet from the heart lung machine to an artery in theorgan donor to form a closed extracorporeal blood circulation in fluidcontact with the organ donor circulatory system; d) operating theheart-lung machine in said operational mode to take venous blood fromthe organ donor, oxygenate the venous blood, and return oxygenated bloodto the organ donor; and e) maintaining the viability of at least oneorgan in said organ donor for subsequent transplantation wherein: saidheart-lung machine comprises a blood reservoir, a blood pump, an airextraction pump, an oxygenator, and a blood filter; the air extractionpump is in fluid communication with an air space at the top of the bloodreservoir and configured to pump air from the blood reservoir; the bloodpump is in fluid communication with and downstream from a blood space atthe bottom of the blood reservoir and in fluid communication with andupstream from the oxygenator; the blood filter is in fluid communicationwith and downstream from the oxygenator; and separate vent lines connectthe top most spaces within each of the oxygenator and the blood filterwith the blood reservoir.
 23. The method of claim 22, wherein said bloodreservoir is separated into a lower blood-containing space and an upperair-containing space by a membrane that is permeable to blood but not toair bubbles.
 24. The method of claim 22, wherein the heart-lung machinefurther comprises: a bubble detector located downstream of said arterialfilter and connected by an arterial line to an arterial connectionconfigured to deliver oxygenated blood to an artery of the patient; anarterial clamp disposed on the arterial line between the bubble detectorand the arterial connection; a bypass line connecting to said arterialline between the bubble detector and the arterial clamp and configuredto transport blood from the arterial line to the blood reservoir; and abypass clamp disposed on the bypass line and wherein the heart-lungmachine is configured such that, when the bubble detector detects an airbubble, the arterial clamp is closed, the bypass clamp is opened, andblood is guided from the bubble detector back into the blood reservoir.25. The method of claim 24, wherein the arterial clamp is opened and thebypass clamp is closed once the blood detector no longer detects an airbubble for a predetermined time interval.
 26. The method of claim 22,comprising maintaining the viability of said at least one organ of theorgan donor by means of the heart-lung machine after harvesting of atleast one organ, transporting said at least one organ to atransplantation location while perfusing the at least one organ duringtransport by means of the heart lung-machine.
 27. The method of claim22, comprising maintaining the viability of said at least one organ ofthe organ donor by means of the heart-lung machine before harvesting ofat least one organ and during transporting said organ donor to atransplantation location while perfusing the body of said organ donorduring transport by means of the heart lung-machine.
 28. A method formaintaining the viability of a harvested donor organ for subsequenttransplantation comprising the steps of: a) priming a heart-lung machinewith a priming liquid in a priming mode; b) switching the heart lungmachine from the priming mode to an operational mode; c) connecting avenous blood inlet on the heart lung machine to a vein in the harvesteddonor organ and connecting an arterial blood outlet from the heart lungmachine to an artery in the harvested donor organ to form a closed bloodcirculation in fluid contact with the circulatory system in theharvested donor organ; and d) operating the heart-lung machine in saidoperational mode to take venous blood from the harvested donor organ,oxygenate the venous blood, and return oxygenated blood to the harvesteddonor organ.
 29. The method of claim 28, wherein: said heart-lungmachine comprises a centrifugal pump head having a central inlet and atangential outlet; and said central inlet to the centrifugal pump headis oriented vertically upward during priming step a) and horizontallyduring operating step d).
 30. The method of claim 28, wherein saidheart-lung machine comprises: a venous connection configured forreceiving blood from a vein of the harvested donor organ; a bloodreservoir separated into a blood-containing space and an air-containingspace by a membrane that is permeable to blood but not to air bubbles,said blood reservoir configured to receive blood from said venousconnection; a centrifugal pump having a central inlet and a tangentialoutlet and configured to draw blood from said blood reservoir and pumpthe blood into an oxygenator; an arterial filter located downstream ofsaid oxygenator; a bubble detector located downstream of said arterialfilter and connected by an arterial line to an arterial connectionconfigured to deliver oxygenated blood to an artery of the harvesteddonor organ; an arterial clamp disposed on the arterial line between thebubble detector and the arterial connection; a bypass line connecting tosaid arterial line between the bubble detector and the arterial clampand configured to transport blood from the arterial line to the bloodreservoir; and a bypass clamp disposed on the bypass line wherein: saidoperating of said heart-lung machine comprises the steps of: e) pumpingblood received from the harvested donor organ through the venousconnection through a blood reservoir and an arterial line to an arterialconnection; f) monitoring for air bubbles in the arterial line usingsaid bubble detector; g) when the bubble detector detects an air bubble,closing the arterial clamp and opening the bypass clamp so that theblood is guided from the bubble detector back into the blood reservoir;h) extracting air from the air-containing space in the blood reservoirusing an air extraction pump; and i) when the blood detector no longerdetects an air bubble, opening the arterial clamp and closing the bypassclamp so that the operating state prevailing before the detection of anair bubble is re-established.
 31. The method of claim 30, wherein: saidblood reservoir comprises a fill level detector in communication withsaid air extraction pump said centrifugal pump; said level detector andsaid air extraction pump are configured to activate said air extractionpump when the blood level detected by the fill level detector in theblood reservoir falls below a first predetermined level; and said leveldetector and said centrifugal pump are configured to shut down saidcentrifugal pump when the blood level detected by the fill leveldetector in the blood reservoir falls below a second predeterminedlevel.
 32. The method of claim 31, wherein said fill level detectorcomprises two fill level sensors located at different positions in theblood reservoir.
 33. The method of claim 28, wherein said heart-lungmachine comprises a peristaltic hose pump comprising: a rotor rotatableby a drive shaft; a support element extending along a part of the rotorperiphery; a flexible hose insertable between the support element andthe rotor; a drive plate rotatable about the drive shaft said driveplate comprising a spiral guide that guides the movement of the supportelement; wherein: the support element is movable by a predetermineddistance in a direction toward the rotor by rotation of the drive shaftin a first direction of rotation; a ring groove is provided in the driveplate into which a fixed position cam guide engages; and the drive platehas at least one guide chamfer, whose lowest point is an opening in thebase of the ring groove, in the region of the opening on the sideopposite the ring groove. wherein: said heart-lung machine comprises afast closing clamp configured to alternately close and open an arterialline in said heart-lung machine, said fast closing clamp comprising: a)a clamp jaw with a clamping position, in which it can pinch off a hose,and an open position; b) a holding apparatus; c) a spring device whichbiases the clamp jaw with respect to the holding apparatus such that theclamp jaw is brought into the clamping position on the relaxation of thespring device; d) a latch device with which the clamp jaw and theholding apparatus can be latched to one another against the spring forceof the spring device in a latched position; and e) a return mechanismfor the movement of the holding apparatus relative to the clamp jawuntil the holding apparatus and the clamp jaw are in their latchedposition relative to one another while the clamp jaw is in the clampingposition, and for the movement of the holding apparatus together withthe clamp jaw into the open position of the clamp jaw after the clampjaw and the holding apparatus with the latching device have been latchedto one another.
 34. The method of claim 33, wherein said fast closingclamp jaw is in an open position that allows a flow of fluid through ahose; the clamp jaw is latched to a holding apparatus by a latch device;the relative longitudinal position between the clamp jaw and the holdingapparatus when latched together is a latching position; the latch deviceis manipulated to unlatch the clamp jaw from the holding apparatus; theclamp jaw moves in the longitudinal direction after being unlatched fromthe holding apparatus to a clamping position by a separating forcetending to move the clamp jaw away from the holding apparatus; the clampjaw prevents the flow of fluid through the hose while in the clampingposition; the holding apparatus is moved relative to the clamp jaw inthe longitudinal direction until the holding apparatus and clamp jaw arein the latching position relative to each other while the clamp jaw isin the clamping position; the clamp jaw is latched to the holdingapparatus using the latch device while the clamp jaw is in the clampingposition; and the holding apparatus and clamp jaw are moved whilelatched together until the clamp jaw is in the open position.
 35. Themethod of claim 28, wherein: said heart-lung machine comprises a bloodreservoir, a blood pump, an air extraction pump, an oxygenator, and ablood filter; the air extraction pump is in fluid communication with anair space at the top of the blood reservoir and configured to pump airfrom the blood reservoir; the blood pump is in fluid communication withand downstream from a blood space at the bottom of the blood reservoirand in fluid communication with and upstream from the oxygenator; theblood filter is in fluid communication with and downstream from theoxygenator; and separate vent lines connect the top most spaces withineach of the oxygenator and the blood filter with the blood reservoir.36. The method of claim 35, wherein said blood reservoir is separatedinto a lower blood-containing space and an upper air-containing space bya membrane that is permeable to blood but not to air bubbles.
 37. Themethod of claim 35, wherein the heart-lung machine further comprises: abubble detector located downstream of said arterial filter and connectedby an arterial line to an arterial connection configured to deliveroxygenated blood to an artery of the harvested donor organ; an arterialclamp disposed on the arterial line between the bubble detector and thearterial connection; a bypass line connecting to said arterial linebetween the bubble detector and the arterial clamp and configured totransport blood from the arterial line to the blood reservoir; and abypass clamp disposed on the bypass line and wherein the heart-lungmachine is configured such that, when the bubble detector detects an airbubble, the arterial clamp is closed, the bypass clamp is opened, andblood is guided from the bubble detector back into the blood reservoir.38. The method of claim 37, wherein the arterial clamp is opened and thebypass clamp is closed once the blood detector no longer detects an airbubble for a predetermined time interval.